XTRM Butyl Polysul-Grip tape is 100% solid preformed synthetic polymer based adhesive/selant tape which has excellent adhesion to aluminum, glass, galvanized steel, and many other porous & non-pourous surfaces. Adhesion improves with age and remains permanently flexible, even at low temperatures.Butyl rubber is the primary seal for all roof penetration. Every screw that punctures the membrane is primarily sealed by XTRM PLY Butyl. RMA Butyl won't crack under changes to temperature or the vibration from road travel.